[American Motorcyclist Association] - New for 2017: Kawasaki KX 250F

[Ninjette Newsbot]

The following is an industry press release...

The new Kawasaki KX250F motorcycle packs more power, better handling and less weight to provide a bike that builds champions.

The Kawasaki KX250F is the single-most dominant motocross bike of the last decade. To keep riders on the podium, Kawasaki introduces an all-new KX250F for 2017, in line with the updates of the KX™450F motorcycle last year. The 2017 model offers a more powerful engine, a significantly lighter chassis, and slimmer ergonomics, making this new model the fastest KX250F motorcycle yet.

The 2017 Kawasaki KX250F:

• Lighter weight (229.9 pounds)
• New more powerful and lighter engine
• New redesigned more narrow and lighter weight frame
• Improved clutch and shift feeling
• New flatter seat and a new lower/flatter tank, for improved handling and ergonomics

This year’s KX250F is built with race-winning components to keep Kawasaki riders in that top spot at the race track. From the showroom to the racetrack, the performance of Kawasaki’s KX family of motorcycles is proof of its engineering pedigree. It truly is the bike that builds champions.

ENGINE

• New redesigned engine with offset cylinder layout, for more efficient power
• Lighter bridged-box bottom piston, designed from racing experience
• Downdraft-style intake layout with new injector angle designed for optimum fuel atomization
• New downstream injector with twice as many holes, finer fuel droplets and wider angle, resulting in stronger low-to-mid power and sharp response
• New and improved combustion chamber configuration
• New 43mm throttle body

Tuned to best suit race-experienced riders, the 249cc liquid-cooled, 4-stroke single’s wide power-band focuses on high-rpm performance that extends way into the over-rev. Highly acclaimed for its high output and smooth power delivery, the 2017 model KX250F has race-inspired tuning and parts like the high-performance bridged-box bottom piston and down draft-style intake routing. Mechanical friction is reduced thanks to things like an offset cylinder—with increased forward lean angle—and plateau honing, resulting in a stronger low end as well as an increase in maximum peak power. The connecting rod now features a journal bearing in lieu of a needle bearing and items like the camshaft sprockets and chain have been revised along with a newly revised exhaust camshaft, all factors resulting in more efficient power.

The KX250F dual-injector fuel injection system is a key component to its performance; introduced in 2012, it was the world’s first to be featured on a production motocross bike. Unlike a standard digital fuel injection that uses one injector downstream of the throttle valve, the KX250F system uses a second, upstream injector located close to the airbox. The downstream injector—redesigned for 2017—is used to help ensure smooth, instant response featuring a finer atomization with more holes in the injector itself. The downstream injector creates that stronger low-to-mid range power and quick throttle response, while the upstream injector is charged with providing power.

As rpm and throttle position increase, primary operation switches from the downstream injector to the upstream injector, depending on whether in a low (1st, 2nd) or high (3rd, 4th, 5th) gear, the transition is gradual or almost instantaneous. The upstream injector’s greater distance from the combustion chamber gives the fuel particles and intake air more time to mix, as well as allowing the mixture to cool before entering the combustion chamber, both of which contribute to more efficient filling, and ultimately more power.

The 2017 model also features revised ECU settings, along with a new exhaust system. The exhaust header pipe is skinnier and shorter, resulting in improved performance.

TUNING

• Lightweight ECU, with revised settings
• Three engine maps (standard, hard, soft) contained in the ECU
• Optional KX FI Calibration Kit (Handheld) requires no tools, laptop or battery

The lightweight ECU of the KX250F motorcycle was designed specifically to withstand the rigors of motocross racing, while still providing a wide variety of tuning. The Kawasaki KX250F provides three engine maps that come pre-loaded into the motorcycle’s ECU that are easily accessible through the DFI® coupling plug. These three color-coded couplers are designed to tune for hard, medium or soft track surfaces, and allow riders to find the perfect power delivery for a particular terrain.

Using the optional KX FI Calibration Kit (Handheld), sold separately as a Kawasaki Genuine Accessory, a rider can store and select from up to seven separate engine maps. The kit includes a portable handheld calibration tool, which enables riders to make changes to the engine maps without the need of a PC, laptop or battery, making it easy to tune at the track. It plugs in thanks to an additional harness not included in the kit.

FRAME & SUSPENSION

• New Swingarm design with improved linkage ratio
• Lighter weight and more rigid frame design
• 6mm narrower frame design
• Showa 48mm Separate Function Front Forks (SFF Type 2)

Changes for the KX250F start at the frame, with a newly redesigned, lighter aluminum perimeter with a new front downtube and 3mm narrower main beams, for an overall reduction width of 6 mm. The frame rigidity has been optimized to obtain improved front end feel.

Up front you’ll find Showa 48mm Separate Function Front Forks (SFF Type 2) with works-style internal construction that locates its damping assembly in the left fork tube and a spring in the right. The Separate Function Front Fork construction contributes to a planted feel at the front, superb damping performance and ride comfort with greater bottoming resistance. It also has excellent stability when on the brakes or when landing jumps. For 2017, revised settings contribute to greater stability over braking bumps and through corners.

The Uni-Trak® rear suspension with Showa shock now features revised valve settings and linkage ratios, contributing to improved ride feel and traction and increased rear-end feedback. A lighter shock spring this year means a weight savings, and the lower rate contributes to the reduced pitching effect over braking bumps. The rear shock linkage mounts are below the swingarm to maximize wheel travel and the new linkage geometry increases cornering stability. Dual compression with high and low speed adjustability offers a wide range of tuning options. Self-lubricating alumite coating on the inner shock body improves wear resistance and shock action.

STYLING & ERGONOMICS

• Easier for the rider to change position while riding
• Integrated bodywork for seamless rider interface
• Aggressive KX body work and in-mold graphics

The all-new minimalist bodywork includes slimmer shrouds, thanks to the revised radiators and their new orientation. The KX250F now features a new flatter and larger capacity fuel tank, along with a new flatter seat with reinforcing ribs. The combination of the new tank and seat aid in a more seamless design, which also makes it easy for riders to move around on top of the bike.

Aggressive all-new bodywork, which includes front and rear fenders, number plate and fork guards, makes the bike look more compact and is complemented by factory-style design and Kawasaki’s first in-mold graphics on the radiator shrouds. Black Excel rims, black fork guards, and green highlights help create a distinctive Kawasaki identity.

Returning this year are ERGO-FIT™ adjustable handlebars and footpegs to better suit riding styles and different rider statures. The handlebars have four position options and the footpegs have two placements available.

LAUNCH CONTROL

For pro riders and amateur riders alike, the KX Launch Control is a major advantage in getting out of the starting gate straight and fast. Launch Control Mode has the greatest effect within the first few seconds of releasing the clutch off the start. The KX250F features a Launch Control system that, with the simple press of a button, allows riders to activate a separate engine map designed to assist starting in certain conditions. The Launch Control Mode map retards ignition timing, allowing tires to gain grip in low-traction situations, and allowing riders to focus on their lines. Launch Control remains active through first and second gear, until the rider shifts into third gear, and then it returns to normal engine timing. Even for top-level riders, controlling the hard-hitting power of a KX250F motocrosser off the start requires a high degree of throttle control and clutch finesse. By optimizing this power, Launch Control Mode helps riders maximize traction, increasing the chance of getting a good start.

BRAKES

Contributing to the racing components found throughout the KX250F are the brakes, with 270mm petal-style disc brakes in the front. These brakes deliver strong braking force and superb control. The petal style discs contribute to both sporty looks and a high-quality appearance. Rear caliper guard protects the caliper from damage.



Click here for full story...